/* Copyright  (c) 2002 Graz University of Technology. All rights reserved.
 *
 * Redistribution and use in  source and binary forms, with or without 
 * modification, are permitted  provided that the following conditions are met:
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 * 1. Redistributions of  source code must retain the above copyright notice,
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 *
 * 2. Redistributions in  binary form must reproduce the above copyright notice,
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 *    and/or other materials provided with the distribution.
 *  
 * 3. The end-user documentation included with the redistribution, if any, must
 *    include the following acknowledgment:
 * 
 *    "This product includes software developed by IAIK of Graz University of
 *     Technology."
 * 
 *    Alternately, this acknowledgment may appear in the software itself, if 
 *    and wherever such third-party acknowledgments normally appear.
 *  
 * 4. The names "Graz University of Technology" and "IAIK of Graz University of
 *    Technology" must not be used to endorse or promote products derived from 
 *    this software without prior written permission.
 *  
 * 5. Products derived from this software may not be called 
 *    "IAIK PKCS Wrapper", nor may "IAIK" appear in their name, without prior 
 *    written permission of Graz University of Technology.
 *  
 *  THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESSED OR IMPLIED
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 */

package iaik.pkcs.pkcs11;

import iaik.pkcs.pkcs11.wrapper.PKCS11Constants;
import iaik.pkcs.pkcs11.wrapper.PKCS11Exception;



/**
 * Interface for notification callbacks. Object implementing this interface
 * can be passed to the openSession method of a token.
 *
 * @author <a href="mailto:Karl.Scheibelhofer@iaik.at"> Karl Scheibelhofer </a>
 * @version 1.0
 * @invariants
 */
public interface Notify {

  /**
   * This is the code to return in a PKCS11Exception to signal surrender
   * to the library.
   */
  public static final long CANCEL = PKCS11Constants.CKR_CANCEL;

  /**
   * The module calls this method in certain events. 'Surrender' is the only
   * event defined by now. If the application wants to return an error code,
   * it can do this using PKCS11Exceptions. Throwing no exception means a
   * return value of CKR_OK, and trowing an PKCS11Exception means a return
   * value of the error code of the exception; e.g.<code><br>
   * throw new PKCS11Exception(PKCS11Constants.CKR_CANCEL);<br>
   * </code><br>
   * causes a return value of CKR_CANCEL.
   *
   * @param session The session performing the callback.
   * @param surrender See CK_NOTIFICATION in PKCS#11. A return value of CKR_OK
   *                  is generatd, if this method call returns regularly.
   *                  CKR_CANCEL can be returned to the module by throwing a
   *                  PKCS11Exception with the error-code CKR_CANCEL.
   * @param application The application-object passed to openSession.
   * @exception PKCS11Exception If the method fails for some reason, or as
   *                            PKCS11Exception with error-code CKR_CANCEL
   *                            to signal the module to cancel the ongoing
   *                            operation.
   * @preconditions (session <> null)
   * @postconditions
   */
  public void notify(Session session, boolean surrender, Object application) throws PKCS11Exception;

}
